Differential expression of long non-coding RNAs under Peste des petits ruminants virus (PPRV) infection in goats

Peste des petits ruminants (PPR) characterized by fever, sore mouth, conjunctivitis, gastroenteritis, and pneumonia, is an acute, highly contagious viral disease of sheep and goats. The role of long non-coding RNAs (lncRNAs) in PPRV infection has not been explored to date. In this study, the transcriptome profiles of virulent Peste des petits ruminants virus (PPRV) infected goat tissues – lung and spleen were analyzed to identify the role of lncRNAs in PPRV infection. A total of 13,928 lncRNA transcripts were identified, out of which 170 were known lncRNAs. Intergenic lncRNAs (7625) formed the major chunk of the novel lncRNA transcripts. Differential expression analysis revealed that 15 lncRNAs (11 downregulated and 4 upregulated) in the PPRV infected spleen samples and 16 lncRNAs (13 downregulated and 3 upregulated) in PPRV infected lung samples were differentially expressed as compared to control. The differentially expressed lncRNAs (DElncRNAs) possibly regulate various immunological processes related to natural killer cell activation, antigen processing and presentation, and B cell activity, by regulating the expression of mRNAs through the cis- or trans-regulatory mechanism. Functional enrichment analysis of differentially expressed mRNAs (DEmRNAs) revealed enrichment of immune pathways and biological processes in concordance with the pathways in which correlated lncRNA-neighboring genes were enriched. The results suggest that a coordinated immune response is raised in both lung and spleen tissues of the goat through mRNA-lncRNA crosstalk.

ACC deaminase and antioxidant enzymes producing halophilic Enterobacter sp. PR14 promotes the growth of rice and millets under salinity stress

Rhizobacteria are known to ameliorate salinity stress through a wide variety of mechanisms including the production of aminocyclopropane-1-carboxylate deaminase (ACCD). Application of ACCD positive halophilic rhizobacteria ameliorate soil salinity along with its plant growth promotion activity. An effect of the inoculation of ACCD and antioxidant positive and halophilic Enterobacter sp. PR14 was reported on the seed germination and growth of rice and millet seedlings grown in saline and alkaline soil was evaluated. The rhizobacterial strain grew well over a high level of NaCl (15-90 M); at a wide range of pH (5-9); and produced a wide variety of plant growth-promoting (PGP) traits viz. indole-acetic acid (13 µg mL-1), ACCD (5.20 M mg-1 h-1), phosphate solubilization (0.99 g mL-1) and antioxidant enzymes such as superoxide dismutase (5.143 IU mg-1 protein), catalase (0.43 IU mg-1 protein) and glutathione (19.077 µg mg-1 protein) during log phase (30 h) of its growth. The stress with alkaline pH (9) and high salinity (90 M) caused a further increase in the synthesis of PGP traits, ACCD, and antioxidant enzymes. The combined application of Enterobacter sp. PR14, ammonium sulfate (as a substitute of ACC), and NaCl (30 M) resulted in a further increase in the seed germination and vigor in rice and millets vis-à-vis control and other treatments. After 15 days of growth, 61.72% more seed germination in rice and millet and 63.15% increase in sorghum was recorded over the control, and after 30 days of growth, 99.67%, 30%, and 54%, root length 50%, 30% and 54% shoot length in rice, sorghum and millet were observed respectively. A significant increase of 38.13%, 30.75%, and 16.36% in dry weight of rice, sorghum, and millet shoots was recorded respectively. Enterobacter sp PR 14, showing multiple plant growth-promoting traits has a great potential to be used as an efficient bioinoculant for growth promotion of rice and millets under alkaline and saline conditions.

Advances in nanomaterials induced biohydrogen production using waste biomass

Recent advances on biohydrogen production using different types of waste biomass with the implementation of nanomaterials are summarized. Inspired by exceptional physicochemical and catalytic properties of nanomaterials, the present review focuses on several approaches including impact of nanomaterials on cellulosic biohydrogen production, possible pretreatment technology, as well as improved enzyme & sugar production in order to enhance the biohydrogen yield. Particularly, impacts of nanomaterial are elaborated in detail on different pathways of biohydrogen production (e.g. dark fermentation, photo-fermentation and hybrid-fermentation) using variety of waste biomass. Additionally, emphases are made on the feasibility of nanomaterials for making the biohydrogen production process more economical and sustainable and hence to develop advanced techniques for biohydrogen production using waste biomass.

A novel strategy to enhance biohydrogen production using graphene oxide treated thermostable crude cellulase and sugarcane bagasse hydrolyzate under co-culture system

Graphene oxide (GO) treated thermostable crude cellulase has been obtained via fungal co-cultivation of strain Cladosporium cladosporioides NS2 and Emericella variecolor NS3 using mix substrate of orange peel and rice straw under solid state fermentation (SSF). Enzyme activity of 60 IU/gds FP, 300 IU/gds EG and 400 IU/gds BGL are recorded in the presence of 1.0% GO in 96 h. This crude enzyme showed 50 °C as optimum incubation temperature, thermally stable at 55 °C for 600 min and stability in the pH range 4.5-8.0. Further, 70.04 g/L of sugar hydrolyzate is obtained from enzymatic conversion of 3.0% alkali pre-treated baggase using GO treated crude cellulase. Finally, 2870 ml/L cumulative biohydrogen production having bacterial biomass ∼2.2 g/L and the complimentary initial pH 7.0 is recorded from sugar hydrolyzate via dark fermentation using co-culture of Clostridium pasteurianum (MTCC116) and a newly isolated Bacillus subtilis PF_1.

Recent development on sustainable biodiesel production using sewage sludge

Biodiesel as a renewable energy is an important alternative to biofuels in current scenario to explore green energy sources. It is well known that the major cost involved in biodiesel production technology is dependent upon the used feedstock. This review presents an overview of biodiesel production using municipal sewage sludge as a cost-effective substrate. Municipal sewage sludge which possesses high lipid content with zero cost availability can meet the characteristics of a potential feedstock to produce biodiesel. Different types of substrates based processes to produce biodiesel have been also explored in brief. In addition, limitations of the existing process technology for biodiesel production with sustainable solutions have been also discussed.

Overcoming antibiotic resistance: Is siderophore Trojan horse conjugation an answer to evolving resistance in microbial pathogens?

Comparative study of siderophore biosynthesis pathway in pathogens provides potential targets for antibiotics and host drug delivery as a part of computationally feasible microbial therapy. Iron acquisition using siderophore models is an essential and well established model in all microorganisms and microbial infections a known to cause great havoc to both plant and animal. Rapid development of antibiotic resistance in bacterial as well as fungal pathogens has drawn us at a verge where one has to get rid of the traditional way of obstructing pathogen using single or multiple antibiotic/chemical inhibitors or drugs. 'Trojan horse' strategy is an answer to this imperative call where antibiotic are by far sneaked into the pathogenic cell via the siderophore receptors at cell and outer membrane. This antibiotic once gets inside, generates a 'black hole' scenario within the opportunistic pathogens via iron scarcity. For pathogens whose siderophore are not compatible to smuggle drug due to their complex conformation and stiff valence bonds, there is another approach. By means of the siderophore biosynthesis pathways, potential targets for inhibition of these siderophores in pathogenic bacteria could be achieved and thus control pathogenic virulence. Method to design artificial exogenous siderophores for pathogens that would compete and succeed the battle of intake is also covered with this review. These manipulated siderophore would enter pathogenic cell like any other siderophore but will not disperse iron due to which iron inadequacy and hence pathogens control be accomplished. The aim of this review is to offer strategies to overcome the microbial infections/pathogens using siderophore.

Efficient dark fermentative hydrogen production from enzyme hydrolyzed rice straw by Clostridium pasteurianum (MTCC116)

In the present work, production of hydrogen via dark fermentation has been carried out using the hydrolyzed rice straw and Clostridium pasteurianum (MTCC116). The hydrolysis reaction of 1.0% alkali pretreated rice straw was performed at 70°C and 10% substrate loading via Fe₃O₄/Alginate nanocomposite (Fe₃O₄/Alginate NCs) treated thermostable crude cellulase enzyme following the previously established method. It is noticed that under the optimized conditions, at 70°C the Fe₃O₄/Alginate NCs treated cellulase has produced around 54.18g/L sugars as the rice straw hydrolyzate. Moreover, the efficiency of the process illustrates that using this hydrolyzate, Clostridium pasteurianum (MTCC116) could produce cumulative hydrogen of 2580ml/L in 144h with the maximum production rate of 23.96ml/L/h in 96h. In addition, maximum dry bacterial biomass of 1.02g/L and 1.51g/L was recorded after 96h and 144h, respectively with corresponding initial pH of 6.6 and 3.8, suggesting higher hydrogen production.

Evaluation of fatty acid profile and biodiesel properties of microalga Scenedesmus abundans under the influence of phosphorus, pH and light intensities

The present study dealt with biomass, lipid concentration, fatty acid profile and biodiesel properties of microalga Scenedesmus abundans under different phosphate concentrations, pH and light intensities, one at a time. Among different phosphate concentrations, higher biomass (770.10±11.0mg/L) and lipid concentration (176.87±4.6mg/L) were at the concentration of 60mg/L. Light intensity at 6000lux yielded higher biomass and lipid concentration of 742.0±9.7 and 243.15±9.1mg/L, respectively. The biomass (769.0±12.3mg/L) and lipid (179.47±5.5mg/L) concentration were highest at pH 8 and pH 6, respectively. All the culture treatments showed marked effect on the fatty acid profile and biodiesel properties of the extracted oil. FAME derived biodiesel properties were compared with European biodiesel standards (EN 14214), Indian biodiesel standards (IS 15607) and American biodiesel standards (ASTM D 6751-08) to assess the suitability of algal oil as biodiesel feedstock.

Molecular evolution, characterization and expression profiling of uterine aldoketoreductase 1B5 gene in endometrium of goat (Capra hircus)

Aldoketoreductase 1B5 (AKR1B5), a member of the Aldoketoreductase family, is involved in the production of Prostaglandin F2α (PGF2α) as one of vital prostaglandin F synthase (PGFS). PGs (Prostaglandins) play a crucial role in female reproductive system. In the present study, we cloned and characterized the full-length open reading frame of AKR1B5 gene in Black Bengal (BB) goat. The complete coding sequence of AKR1B5 comprises an entire open reading frame of 951 bp, encoding 316 amino acid (AA) residues. BB AKR1B5 showed >82.9% identity with that of cattle, rabbit, human, and rat at nucleotide and amino acid levels, respectively. Further, a systematic study of AKR1B5 sequence evolution was also conducted using Phylogenetic Analysis by Maximum Likelihood (PAML), entropy plot, and Blossum 62 in a phylogenetic context. Analysis of nonsynonymous to synonymous nucleotide substitution rate ratios (Ka/Ks) revealed that negative selection may have been operating on this gene during evolution in goat, cattle, rabbit, human, and rat, which showed its conservation across species. Further, expression of AKR1B5 was determined by quantitative real-time PCR in goat endometrial tissues at different stages of the estrous cycle and early pregnancy. Our results indicated its high expression at luteolytic phase (stage III; day 16-21) during the estrous cycle. However, during early (day ∼30-40) pregnancy the expression was highest as compared to estrous cycle.

Fresh water green microalga Scenedesmus abundans: A potential feedstock for high quality biodiesel production

Present investigation studied the potential of fresh water green microalga Scenedesmus abundans as a feedstock for biodiesel production. To study the biomass and lipid yield, the culture was grown in BBM, Modified CHU-13 and BG-11 medium. Among the tested nitrogen concentration using Modified CHU-13 medium, the highest biomass and lipid yield of 1.113±0.05g/L and 489±23mg/L respectively was found in the culture medium with 0.32g/L of nitrogen (KNO3). Different lipid extraction as well as transesterification methods were also tested. Fatty acid profile of alga grown in large scale indigenous made photobioreactor has shown abundance of fatty acids with carbon chain length of C16 and C18. Various biodiesel properties such as cetane number, iodine value and saponification value were found to be in accordance with Brazilian National Petroleum Agency (ANP255) and European biodiesel standard EN14214 which makes S. abundans as a potential feedstock for biodiesel production.

Effect of Linum usitatissimum (linseed/flaxseed) fixed oil on experimental esophagitis in albino rats

INTRODUCTION

The present study was undertaken to elucidate the effect of Linum usitatissimum fixed oil on experimental esophagitis in albino rats.

METHODS

Group of rats (n = 6), treated with vehicle control (0.9% NaCl, 3 mL/kg, i.p.) or L. usitatissimum fixed oil (1, 2, 3 mL/kg, i.p.) or omeprazole (30 mg/kg, i.p.). Rats were subjected to pylorus and forestomach ligation to induce esophagitis and were compared to a control sham group. Animals were sacrificed after 6 h and evaluated for the gastric pH, gastric volume, total acidity and esophagitis index. Esophageal tissues were further subjected to estimations of sialic acid, collagen, thiobarbituric acid reactive substances, tissue glutathione, catalase and superoxide dismutase.

RESULTS

Treatment with fixed oil significantly inhibited the gastric secretion, total acidity and esophagitis index. The oil also altered the levels of sialic acid and collagen towards normal with significant antioxidant activity in esophageal tissues.

CONCLUSION

The lipoxygenase inhibitory, histamine antagonistic, antisecretory (anticholinergic) and antioxidant activity of the oil was attributed for its effect in reflux esophagitis.

Progress of tissue culture and genetic transformation research in pigeon pea [Cajanus cajan (L.) Millsp.]

Pigeon pea [Cajanus cajan (L.) Millsp.] (Family: Fabaceae) is an important legume crop cultivated across 50 countries in Asia, Africa, and the Americas; and ranks fifth in area among pulses after soybean, common bean, peanut, and chickpea. It is consumed as a major source of protein (21%) to the human population in many developing countries. In India, it is the second important food legume contributing to 80% of the global production. Several biotic and abiotic stresses are posing a big threat to its production and productivity. Attempts to address these problems through conventional breeding methods have met with partial success. This paper reviews the chronological progress made in tissue culture through organogenesis and somatic embryogenesis, including the influence of factors such as genotypes, explant sources, and culture media including the supplementation of plant growth regulators. Comprehensive lists of morphogenetic pathways involved in in vitro regeneration through organogenesis and somatic embryogenesis using different explant tissues of diverse pigeon pea genotypes are presented. Similarly, the establishment of protocols for the production of transgenics via particle bombardment and Agrobacterium-mediated transformation using different explant tissues, Agrobacterium strains, Ti plasmids, and plant selectable markers, as well as their interactions on transformation efficiency have been discussed. Future research thrusts on the use of different promoters and stacking of genes for various biotic and abiotic stresses in pigeon pea are suggested.

In vitro direct shoot regeneration from proximal, middle and distal segment of Coleus forskohlii leaf explants

Coleus forskohlii is an endangered multipurpose medicinal plant that has widespread applications. In spite of this, there have been few attempts to propagate its cultivation in India. The present communication presents an in vitro rapid regeneration method using leaf explants of Coleus forskohlii through direct organogenesis. Leaf explants that were excised into three different segments i.e. proximal (P), middle (M) and distal (D) were cultured on Murashige and Skoog (MS) basal medium supplemented with cytokinins. MS Media containing 5.0 mg L(-1) BAP (6-Benzylaminopurine) promoted regeneration of multiple shoots through direct organogenesis from the leaf, which were further elongated on MS media augmented with 0.1 mg L-1 BAP and 0.1 mg L(-1) IAA (Indole-3-acetic acid), cytokinin and auxin combination. Regenerated and elongated shoots, when transferred to ose resulted in profuse rooting plants that were transferred to soil after acclimatization and maintained in a green house. The current protocol offers a direct, mass propagation method bypassing the callus phase of C. forskohlii and is suitable for conservation, large-scale commercial cultivation, and genetic transformation with agronomically desirable traits.

Serogroups of Escherichia coli from drinking water

Fifty seven isolates of thermotolerant E. coli were recovered from 188 drinking water sources, 45 (78.9%) were typable of which 15 (26.3%) were pathogenic serotypes. Pathogenic serogroup obtained were 04 (Uropathogenic E. coli, UPEC), 025 (Enterotoxigenic E. coli, ETEC), 086 (Enteropathogenic E. coli, EPEC), 0103 (Shiga-toxin producing E. coli, STEC), 0157 (Shiga-toxin producing E. coli, STEC), 08 (Enterotoxigenic E. coli, ETEC) and 0113 (Shiga-toxin producing E. coli, STEC). All the pathogenic serotypes showed resistance to bacitracin and multiple heavy metal ions. Resistance to streptomycin and cotrimazole was detected in two strains whereas resistance to cephaloridine, polymixin-B and ampicillin was detected in one strain each. Transfer of resistances to drugs and metallic ions was observed in 9 out of 12 strains studied. Resistances to bacitracin were transferred in all nine strains. Among heavy metals resistance to As(3+) followed by Cr(6+) were transferred more frequently.

Biosorption and elution of chromium from immobilized Bacillus coagulans biomass

Bacillus coagulans, a tannery wastewater isolate, previously shown to bind dissolved Cr(VI), retained its ability to biosorb Cr(VI) in different matrices. Polymeric materials like agar, agarose, calcium alginate and polyacrylamide were screened. Agarose emerged as the suitable candidate for biomass immobilization mainly due to its higher stability and integrity in acidic pH. Aptness of agarose as the matrix for B. coagulans biomass was revealed during Cr(VI) biosorption from natural wastewater.

Evaluation of simple microbiol tests for detection of fecal coliforms directly at 44.5 degrees C

Simple microbial test comprising H2S paper strip test, presence-absence (PA) test, and fluorogenic brila broth (BB) test performed directly at 44.5 degrees C were evaluated and compared with the standard most probable number (MPN) method for detection of fecal coliforms in 173 drinking water sources. BB and PA test were comparable with standard MPN method, whereas, poor compliance was noted for H2S test. PA test when compared with standard MPN test only 15% disagreement was detected, whereas, highest disagreement of 40% was observed in case of H2S test. BB test was found to be highly sensitive as only 7.8% disagreement with that of standard MPN test was found. Three hundred cultures obtained from positive tests were identified in order to evaluate the specificities of test used in detection of fecal indicator Escherichia coli. BB test was also found highly specific in detection of indicator organism as compared to PA and H2S test. Among the organisms isolated from BB test 84.4% of them were identified as E. coli as compared to 43.4 and 33.3 in PA and H2S test, respectively. The low incidence of recovery of E. coli (18.1%) for the standard MPN method places doubt on the validity of its application in tropical areas. The result of this investigation suggest that BB performed directly at 44.5 degrees C could be suitable cost effective test to assess the microbiological quality of drinking water in India and other tropical countries.

Chromium (VI) biosorption and bioaccumulation by chromate resistant bacteria

In this study, strains that are capable of bioaccumulating Cr(VI) were isolated from treated tannery effluent of a common effluent treatment plant. The Cr(VI) concentration in this treated effluent was 0.96 mg/l, much above the statutory limit of 0.1 mg/l for discharge of industrial effluents into inland surface waters in India. In addition to the bioaccumulation, biosorption capabilities of living and dead cells were analysed. Two strains, identified as Bacillus circulans and Bacillus megaterium were able to bioaccumulate 34.5 and 32.0 mg Cr/g dry weight, respectively and brought the residual concentration of Cr(VI) to the permissible limit in 24 h when the initial concentration was 50 mg Cr(VI)/l. Our experimental design accounts for initial as well as final residual concentration of heavy metal while selecting heavy metal accumulating strains during batch studies. Biosorption of Cr(VI) was shown by B. megaterium and an another strain, B. coagulans. Living and dead cells of B. coagulans biosorbed 23.8 and 39.9 mg Cr/g dry weight, respectively, whereas, 15.7 and 30.7 mg Cr/g dry weight was biosorbed by living and dead cells of B. megaterium, respectively. Biosorption by the dead cells was higher than the living cells. This was due to prior pH conditioning (pH 2.5 with deionized water acidified with H2SO4) of the dead cells.

Effect of ecological factors on conjugal transfer of chromium-resistant plasmid in Escherichia coli isolated from tannery effluent

The influence of total organic carbon (TOC), pH, and mating temperature on transfer of chromium-resistant plasmid between Escherichia coli strains in terms of variation in the number of transconjugants formed and variation in transfer frequency was investigated. In vitro transfer was studied in five chromate-tolerant E. coli strains isolated from tannery effluent using E. coli K12 J62 (Nal(r) Lac-) as a recipient. Conjugal transfer of different selection markers was observed in three strains. The study was carried out in sterile wastewater. A gradual decrease was observed both in the number of transconjugants and in transfer frequencies as the concentration of TOC in the mating medium descended from 10,095 to 1.2 mg of C/L, obtaining the maximum values with a TOC concentration of 10,095 mg of C/L. The number of transconjugants and the transfer frequency were maximum at 30 degrees C. However, neither the transfer frequency nor the transconjugant number varied significantly in the range of pHs assayed. The strains were also found resistant to different heavy metals and antibiotics. Curing of these strains resulted in loss of one or more resistance markers indicating the plasmid-borne resistance. Itis inferred that plasmid transferby conjugation occurs in wastewater bodies within a wide range of conditions.

Uptake of nickel (II) by Serratia marcescens

Bioaccumulation and biosorption of various nickel salts by Serratia marcescens (NCIM 2078) were investigated Biosorption of nickel was found maximum for the nickel nitrate and nickel chloride as 28.08 and 25.51 mg-1 nickel was obtained in dry biomass of S. marcescens, respectively. The possible role of pigment prodigiosin in uptake of nickel is discussed.

Assessment of industrial effluent and its impact on soil and plants

The present study deals with the assessment of industrial water of an electronic component manufacturing unit with electroplating and its subsequent effects on soil and plants receiving the effluent. The physico-chemical parameters of the effluent samples showed higher value than that of ground water. The treated effluent was within the permissible limit. Microtox test was conducted and determined the degree of toxicity of untreated, treated effluents as well as the water sample collected at effluent discharge point of receiving river (confluence point). The physico- mechanical parameters of the soil samples were not changed due to irrigation of the treated effluent, but the concentration of metals were comparatively higher than the control soil. Higher accumulation of metals was found in the plant parts in naturally growing weeds and cultivated crop plant irrigated with treated effluent. Elevated accumulation of metals in Eichhornia crassipes and Marsilea sp. growing along the effluent channel has been identified as a potential source of biomonitoring of metals particularly for Cu and Ca and can be utilised for the removal of heavy metal from wastewater.

Chromate tolerant bacteria isolated from tannery effluent

The occurrence of metal tolerant and antibiotic resistant organisms was investigated in tannery effluent. Seventy-seven isolates comprising heterotrophs (41) and coliforms (36) which were tolerant to chromate level of > 50 microg/ml were selected for detailed study. The majority of the coliforms were resistant to higher levels of chromate (200 microg/ml) whereas around 3% of the heterotrophs were resistant to Cr6+ at a level of > 150 microg/ml. All chromate tolerant heterotrophs were also tolerant to Cu2+ (100%) whereas only 58.53% coliforms were tolerant to Cu2+. Except in the case of Cd2+ a higher number of heterotrophs were found tolerant to other heavy metals tested. Both groups of isolates were found sensitive to mercury. Resistance to cephaloridine was more abundant (P < 0.001) in coliforms as compared to heterotrophs. On the other hand a significantly higher number (P < 0.01) of heterotrophs showed resistance to streptomycin and carbencillin. All coliforms were sensitive to chloramphenicol. Around 80%) and 31.70% of coliforms and heterotrophs exhibited a relationship to the combination of metals and antibiotics. Both heterotrophs and coliforms tolerant to Hg2+ were also resistant to polymixin-B.

Characterization of large plasmids encoding resistance to toxic heavy metals in Salmonella abortus equi

Salmonella abortus equi vaccine strains were found to be resistant to high levels of toxic heavy metals--arsenic, chromium, cadmium, and mercury. The two strains 157 and 158 were resistant to ampicillin also. Curing of these strains resulted in loss of one or more resistance marker indicating plasmid borne resistance. Plasmid profile of strain 157 showed presence of three plasmids of 85, 54, and 0.1 Kb, whereas 158 strain showed presence of 85 Kb and 2 Kb plasmids. Plasmids were isolated from strain 157 and introduced into E. coli DH5alpha with a transformation efficiency of 2 x 10(3) transformants/microg DNA. Interestingly the transformants were resistant to antibiotics, heavy metals (As, Cr, Cd, Hg) and was also able to utilize citrate, a trait specific to Salmonella species. We report and establish for the first time the transferable large plasmids encoding resistance to various heavy metals, antibiotics and biochemical nature of S. abortus equi.

Potability of water sources in relation to metal and bacterial contamination in some northern and north-eastern districts of India

A total of 1094 water samples from 326 springs, 207 streams, 183 dug wells, 151 piped supplies, 90 tube wells, 75 hand pumps, 60 rivers and 2 lakes were collected from eight northern and six north-eastern districts of India. Samples were analysed to assess their potability by estimating the level of heavy metals and bacterial (coliform and faecal coliform) contaminations. Iron was found in a maximum number (53%) of water samples from hand pumps, followed by lead in 43% of the tube wells, chromium in 16% of dug wells, cadmium in 13% of streams and manganese in 7% of hand pumps above their maximum admissible concentrations (MACs). Maximum metal pollution has been observed in a considerable number of water samples from Doda, followed by Almora, Mirzapur and Bankura. Hand pump water samples exhibited maximum metal pollution followed by dug well, spring, stream and river water samples. Contamination of coliform and/or faecal coliform bacteria ranged between 41% and 67% of water samples from open water sources but it was also less, i.e. 6-15% of water samples from tube wells and hand pumps. In general, 42-85% of water samples from districts surveyed, except from Jammu (18%) and Mirzapur (27%), were found to be bacteriologically unsatisfactory. Since toxic metals and pathogenic bacteria pose a risk to public health, monitoring of drinking water sources is required.

Evaluation of the presence-absence (P-A) test: A simplified bacteriological test for detecting coliforms in rural drinking water of India

One thousand three-hundred and ninety-four drinking water sources comprising ground water, surface water and piped supplies were tested in order to compare the presence-absence (P-A) test with standard MPN method to detect coliforms as indicators of water quality. Out of 1394 samples, 1074 (77.04%) and 1030 (74.88%) were positive by the MPN and P-A test, respectively. The P-A test detected 96% of the positives detected by the MPN test. The P-A test may be effectively used as a rapid screening method to detect coliform contamination in less polluted sources such as ground water and piped supplies.

Riverine pollution in some northern and north eastern states of india

Water samples from 30 rivers in northern and north-eastern hilly states of India were analysed for bacteriological and physicochemical parameters along with metals and pesticide residues. It was found that 34% of samples had >50 coliforms/100 ml, while 24% of samples demonstrated >50 thermotolerant (faecal) coliforms/100 ml. Among the metals, iron was found to be above maximum permissible limits in the rivers of all the states, while manganese was found to be above the maximum permissible limit in the rivers of Tripura and some northern states. Zinc, lead, nickel, chromium, copper, cobalt and cadmium plus physicochemical parameters and residual pesticides, however, were within their maximum permissible limits.

Transferable antibiotic resistance among thermotolerant coliforms from rural drinking water in India

A total of 231 thermotolerant coliforms was isolated from rural drinking water from four states of India. Of these, 220 isolates were resistant to ampicillin, chloramphemicol, streptomycin and tetracycline. Multiple (MAR), double and single antibiotic resistances were observed in 31.4, 48.6 and 13.7% of the isolates, respectively. Out of 177 antibiotic-resistant isolates examined for transmissibility, only 15.3% were able to transfer their resistances to Escherichia coli K-12 recipient. The resistances were transferred by 32.5% of MAR, 21.9% of double resistant and 7.6% of single resistant isolates. Ampicillin resistance was transferable in 14.69% strains while resistances for the rest of the antibiotics were transferable in less than 4% strains. MAR strains of E. coli and Klebsiella sp. showed highest levels of R-plasmid transfer.

Evaluation of coliforms as indicators of water quality in India

The total and thermotolerant coliform counts in rural drinking water derived from ground water, piped supplies and surface water are reported for a number of areas in India. To evaluate these counts as indicators of recent faecal contamination the total coliforms and thermotolerant coliforms isolated have been identified. Thermotolerant Escherichia coli formed 11.7% of the total coliforms and 75.1% of the thermotolerant coliforms. Citrobacter sp. (20.4%) and Klebsiella sp. (50.9%) were the other common total coliforms isolated and, among the thermotolerant coliforms, Klebsiella sp. (16.4%) was the only other organism frequently encountered. The total coliform counts were significantly correlated with water temperature. The applicability in tropical areas of standards developed for temperate climates is discussed.

Antibiotic resistance of coliforms in drinking water in rural areas

The antibiotic sensitivity of 197 coliform sp. isolated from drinking water in five rural areas was studied. Twelve strains (6.1%) showed multiple antibiotic resistance, three (1.5%) of which were able to transfer the resistances to an Escherichia coli K-12 recipient. It seems unlikely that the occurrence of transmissible multiple antibiotic resistance among coliforms in drinking water in the areas studied poses a significant public health risk.